1. Field of the Invention
The invention relates to the field of portable handheld lighting devices and in particular to LED flashlights.
2. Description of the Prior Art
The minimum requirements for a common flashlight are: an energy source, typically a battery or batteries, a light source, usually an incandescent lamp, or more recently an LED or an array of LEDs, a means of switching the energy on and off, and a case or housing. LED flashlights are advantageous in that they typically have longer lamp and battery lives, due in large part to their lower power consumption and lower operating temperatures as compared to incandescent units. The better designed LED flashlights have the same or a greater illumination intensity than comparable incandescent units operating at the same or higher power.
However, LED flashlights have typically demonstrated lower beam intensity than conventional incandescent flashlights. Typical LED flashlight implementations generate a broad, unfocused beam, or a small center spot of higher intensity with a broad splash of lower intensity light surrounding the center spot. The illumination factors of intensity, beam shape and beam distribution are mostly controlled by the configuration of the components, not by the designer.
What is needed is a design that focuses or concentrates the broad energy pattern of the LED into a beam, whose shape and intensity is fully controlled at the time of design by the choice of surface contours of its reflector and are not limited by the configuration.